Cowpea

Cowpea is an important legume crop in Sri Lanka. It is an inexpensive souse of protein and a hardy crop well adapted to relatively dry environments.

Extent, Production and Export (1997 to 2001)

Year	Extent(ha)	Production(mt)	Export(Kg)
1997	16209	13971	200
1998	14827	13399	500
1999	13149	12106	70
2000	12947	12121	-
2001	10976	10072	06

Areas Cultivated

Hambantota, Ratnapura, Badulla, Monaragala, Anuradhapura, Kurunegala, Puttlum, Batticalo, System 'H', Ampara, Polonnaruwa.

Recommended Varieties
MI 35, Wijaya, Waruni, Dhawala and Bombay

Varietal Characteristics
MI 35

Exhibits semi-erect growth habit Flowering occurs in about 45 days after planting. Flowers are white in colour. Pods are borne about the canopy. Seeds are small and pure cream in colour. Thousand seed weight average around 70g. Current yield is 1350kg ha-1 . Variety MI35 is susceptible to collar rot disease.

Wijaya

This variety exhibits erect and determinate growth. It flowers in about 40-45 days after planting. Flowers are bluish purple in colour. Pods are long pendulous and dark green. Seeds are large and light brown in colour. This variety matures in about 55-60 days. It has a thousand seed weight of 100g. Average yield 1600 kg ha-1. Resistance to collar rot disease.

Waruni

Plant exhibits erect and determinate growth habit. It flowers in about 40 days after planting. It has bluish purple flowers. It bears long pendulous dark green pods. Medium sized seeds and reddish brown in colour. It has a thousand seed weight of about 115g. Average yield 1650 kg ha-1.

Dhawala

Dhawala exhibits a semi erect growth habit. Flowering occurs in 40-45 days after planting. Flowers are white in colour. Pods are pendulous and green in colour. Seed are large and cream coloured with a black eye. Its thousand seed weight is 170g. Variety Dhawala is suitable for planting in will drained paddy lands during yala season. Average yield 1600 kg ha-1.

Bombay

Exhibits erect growth habit. Flowering occurs is about 40-50 days after planting. Flowers are purple in colour. It posses dark green pigmented long and pendulous pods. It matures in 75-90 days after planting seed are large and speckled grey brown in colour. Thousand seed weight in about 180g Variety Bombay cowpea in suitable for cultivation in Maha season in rainfed uplands. Average yield 1450 kg ha-1.

Field Establishment
Environmental and growth requirement

Soil
Cowpea can be grown on a wide range of soil, from predominantly sandy loam to clay ranging from acidic to basic (pH 4.5 - 8.0). Sandy to clay loam soil and well drained with a pH of 6-7 Cowpea are highly sensitive to water logging.

Cowpea is a warm weather crop which grows at temperatures between 20c to 30c

Land Preparation
One ploughing followed by a harrowing ensures good weed control and a suitable seed bed.

Seed rate
35 - 40 kg/ha

Time of planting
Plant cowpea when there is sufficient soil moisture for germination.

Season
Yala -(Irrigated)- April
Maha -( Rainfed )End of October to Mid November.

Planting method
Rain-fed plant directly on flat or raised beds. Plant manually or with a row seeder on ridges or flat beds depending on field drain age. Plant one plant /hill with a spacing of 30 cm between rows 15 cm between plants.

Crop Management

Fertilizer
Basal N 30 kg/ha     (urea 35 kg/ha-1)

P2O5 45kg/ha    (Triple super phosphate 100kg/ha-1)
K2O 45kg/ha    (Muriate of portash 75 kg/ha-1)

Top dressing 30kg/ha of urea at onset of flowering

Irrigation Frequency of application Every 4 days during first 3 weeks and then every 7 days
Pruning When cowpea is grown on very fertile soil or when irrigation is excessive during the
vegetative phase. Irrigation should be reduced or vine pruned.
Weed control 3 and 6 weeks after planting weeding is usually manual.
Chemical weed control
Alachlor        3.3 - 3.5 l ha-1
Oxyfluorfen    0.50 - 0.75 l ha-1
Metalochlor    3.0 - 4.0 l ha-1

Insect Control
Insect     Chemical    Dosage per ha (l/ha-)

Leaf hoppers    Dimethioate 40% E.C    490 - 700 ml
Endosulfan 35% E.C     560 - 770 ml

Pod borers     Methomidophos 50% E.C     1400 - 2100 ml
Aphids, scale & Mealy bugs    Dimethoate     910 - 1820 ml

Disease
Collar rot    caused by
Pythium aphanidermatum
Rhizoctonia sp
Selerotium rolfsii
Fusariam

Control
i. Use a recommended fungicide as a soil drench.
ii. Avoid continuous cropping of cowpea on the same field.
iii. Avoid excessive N2 application.
Fungal wilt    Funaruin oxysporium

Anthracnose    Collectotrichum lindemuthianum

Web blight - Rhizoctonia solani
Symptoms
Small circular reddish brown spots on leaves enlarge and become irregularly shaped water soaked areas.Mycllia of Rhizoctonia solani are visible on the under surface of leaves and on young stems

Control
1. Use disease free seed
2. Avoid dense planting
3. Use a fungicide recommended for Rhizoctonia

Cowpea yellow mosaic virus
Symptoms
Leaf symptoms vary from green mottle to severe mosaic
Leaf distortion blistering and plant death

Control
1. Use resistant cultivars
2. Plant disease free seeds
3. Control vectors with insecticides